I. Field of the Invention
The present invention relates generally to dosimeters and, primarily, to an ultraviolet dosimeter for use by sunbathers.
II. Description of the Prior Art
There are a number of previously known dosimeters which measure the accumulative exposure of a sensor to radiation, such as light. A number of these previously known dosimeters also include optical filters which limit the measured radiation to a predefined range, such as ultraviolet light, and a number of these dosimeters are designed for use by sunbathers in order to prevent sunburns. Examples of these previously known devices can be found in U.S. Pat. No. 3,710,115 to Jubb and U.S. Pat. No. 3,917,948 to Strutz.
Many sunbathers apply a cream or lotion to their skin to protect it from excessive dosage of ultraviolet radiation from the sun and so that the user can remain in sun for longer periods of time without suffering from sunburn. However, it is difficult to determine the accumulative radiation that the sunbather has received since the accumulative radiation depends not only upon the intensity of the sunlight, but also the angle of incidence. In addition, the radiation dosage a sunbather can sustain without burning of the skin depends upon the solar protection factor (SPF) of the sunscreen material.
These previously known dosimeters used by sunbathers do not compensate for the SPF value of sunscreen lotions or creams. The SPF value for such sunscreen lotions or creams are established by the Federal Food and Drug Administration.